How Long Will $100,000 Last?
$100,000 is a significant nest egg that can provide 2-4 years of financial runway depending on your lifestyle. At $4,000/month expenses, $100k lasts about 25 months. With investment returns and careful planning, you can extend this considerably. Use our calculator to see your personalized timeline.
By Sammy S. · Founder · AuthorUpdated for 2026
$100,000
Starting savings
~25 months
At $4,000/mo
$24,000
6-month fund
$4,000
Per year (4% rule)
Key facts
2.7% annually (US)
Defaults: $50,000 savings · $3,500/mo expenses. Results update as you type.
| Monthly expenses | Duration |
|---|---|
| $2,000/mo | 4y 2mo |
| $2,500/mo | 3y 4mo |
| $3,000/mo | 2y 9mo |
| $3,500/mo | 2y 5mo |
| $4,000/mo | 2y 1mo |
| $4,500/mo | 1y 10mo |
| $5,000/mo | 1y 8mo |
| $6,000/mo | 1y 5mo |
Without income or inflation. Use calculator for full details.
Expert tips
Keep $100k growing: even in savings, 4-5% APY adds $4-5k/year
Consider the 4% rule for retirement: $100k supports $4,000/year indefinitely
Geographic arbitrage: $100k lasts 5-8 years in many countries abroad
If under 50, keep investing - $100k at 7% becomes $200k in 10 years
Don't forget taxes on withdrawals from 401k/IRA accounts
The runway duration above comes from your savings, monthly expenses, income, optional one-time costs, and inflation setting—not a third-party feed. We simulate month by month: each period we subtract expenses (and add income), optionally growing expenses for inflation, until the balance reaches zero or income covers spending. Below are the formulas, the order we follow, and worked examples you can check by hand.
Formulas
| Line | Formula |
|---|---|
| Effective savings | Current savings − one-time expense (minimum 0) |
| Monthly burn (no inflation) | Monthly expenses − monthly income |
| Quick estimate (no inflation) | ⌈Effective savings ÷ monthly burn⌉ months |
| Monthly inflation factor | (1 + annual inflation % ÷ 100)^(1/12) applied each month after month 1 |
| Each simulated month | Balance = prior balance − expenses + income |
| Indefinite runway | When monthly income ≥ monthly expenses, savings do not deplete |
Order of operations
Start with usable savings
Subtract any one-time expense from current savings
Planned large purchases (moving costs, medical bills) reduce the balance available for ongoing monthly spending before the simulation begins.
Compute monthly burn
Expenses minus income each month
If income fully covers expenses, runway is indefinite—the calculator stops with a message that savings will remain stable or grow.
Simulate month by month
Subtract net burn until balance ≤ 0
We count each month until savings are exhausted. This matches how emergency funds are actually drawn down over time, not a single lump-sum division.
Grow expenses when inflation is on
Multiply monthly expenses by monthly inflation rate after month 1
Simple mode uses one annual inflation rate (country default or your custom rate). Advanced mode can apply category-specific rates, spending levels, and emergency events.
Report duration and per-paycheck context
Total months → years + months; build timeline chart
The headline duration is the month count when balance hits zero. We also show monthly breakdown rows (up to 120 months) for the chart.
Worked example
How Long Will $100,000 Last?
Effective savings: $100,000
Monthly burn: $4,000 − $0 = $4,000/mo
Runway: 25 months (2 years and 1 month)
No-inflation check: $100,000 ÷ $4,000 ≈ 25 months (simulation may add 1 month when balance goes negative mid-period)
| Line item | Amount |
|---|---|
| Current savings | $100,000 |
| One-time expense | $0 |
| Effective savings | $100,000 |
| Monthly expenses | $4,000 |
| Monthly income | $0 |
| Monthly burn | $4,000 |
| Total months | 25 |
| Duration | 2 years and 1 month |
One-time cost: One-time $5,000 expense before monthly drawdown → 1 year and 1 month.
Inflation on: With US inflation enabled (2.7% planning rate) → 1 year and 3 months (avg expense $3,556/mo).
Constants we use
| Parameter | What we use |
|---|---|
| Default savings | $50,000 |
| Default monthly expenses | $3,500 |
| Default monthly income | $0 |
| Inflation default (US) | 2.7% annual |
| Simulation cap | 1,200 months (100 years) |
| Chart breakdown cap | 120 months |
What we do not model on this page
Simple mode uses flat monthly expenses and income unless inflation is enabled—we do not model investment returns on savings, variable paycheck timing, taxes, or exact pay dates. Advanced mode adds spending levels, income stops, emergency events, and category inflation but is still a planning estimate. Inflation rates are long-term planning assumptions, not live CPI feeds. Results are illustrative, not financial advice.
FAQ
Frequently asked questions — How Long Will $100,000 Last?
Runway math, emergency funds, income, inflation, and planning tips for how long will $100,000 last?.
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Disclaimer: This calculator provides estimates for planning purposes only. Actual results may vary based on unexpected expenses, market conditions, and changes in your financial situation. Consult a certified financial planner for personalized advice.